WebPack 5 ready manifest plugin.

manifestPlugin.ts

import { Compilation, Compiler, sources } from 'webpack';

interface Options {
  filename: string;
}

interface Manifest {
  [key: string]: string[];
}

export class ManifestPlugin {
  private options: Options;

  constructor(options: Partial<Options> = {}) {
    this.options = {
      filename: 'manifest.json',
      ...options,
    };
  }

  public apply(compiler: Compiler) {
    let manifest: Manifest = {};

    compiler.hooks.compilation.tap('ManifestPlugin', (compilation) => {
      compilation.hooks.processAssets.tap({
        name: 'ManifestPlugin',
        stage: Compilation.PROCESS_ASSETS_STAGE_ADDITIONS,
      }, (assets) => {
        const stats = compilation.getStats();
        for (const chunk of stats.compilation.chunks) {
          manifest[chunk.name] = Array.from(chunk.files.values());
        }
        assets[this.options.filename] = new sources.RawSource(JSON.stringify(manifest), true);
      })
    })
  }
}